Philip Bobbitt is Herbert Wechsler Professor of Federal Jurisprudence and Director of the Center for National Security at Columbia University. He has served as a senior adviser at the White House, the Senate and the State Department in both Democratic and Republican administrations, and has held senior posts at the National Security Council, including Director for Intelligence Programs and Senior Director for Strategic Planning. He was Anderson Senior Research Follow at Nuffield College, Oxford, where he was a member of the Oxford Modern History Faculty, and Marsh Christian Senior Fellow of War Studies at King's College, London, and is currently Senior Fellow in the Robert S. Strauss Center for International Security and Law at the University of Texas. He is a member of the American Academy of Arts and Sciences and has written books on nuclear strategy, social choice and constitutional law, as well as the celebrated The Shield of Achilles (Allen Lane/Penguin 2002). He lives in New York, Austin and London.